Constrained geometry olefin polymerization catalysts derived from TMCp are known. See, generally, DeVore, et al. (1995) Organometallics 14: 3132-3124; U.S. Pat. No. 5,470,993; European patent application 0 416 815 A2; published application Ser. No. WO98/27103; Shapiro, P. J., et al., (1990) Organometallics 9: 867-869; and Shapiro, P. J., et al., (1994) J. Am. Chem. Soc. 116: 4623-4640. The synthesis of these catalysts may include the conversion of substituted cyclopentadienyl silyl amines (CpSA ligands) of Formula I: ##STR1## in which R may be an atom alkyl group, preferably having one to five carbon atoms, R.sup.1 and R.sup.2 are alkyl groups, wherein R.sup.1 is preferably methyl and R.sup.2 is preferably tertiary butyl. Each of R.sup.1 and R.sup.2 may be the same as or different from each other and from any R. The ligands may be converted to Group IV metal dichloride compounds of Formula II: ##STR2## in which M is a Group IV metal, preferably zirconium, hafnium or titanium, and R, R.sup.1 and R.sup.2 are as defined.
As the cited references show, the Formula II dichloride may be reacted with a diene, typically 1,3-pentadiene, to produce a constrained geometry metallocene complex useful as an olefin polymerization catalyst.